Retrievable well packer



Jan. 21, 1969. M. B. com 3,422,901

RETRIEVABLE WELL PACKER I N VEN TOR. M1? 77/V COA/P40 VMM@ Jan. 21, 1969l L a, CQNRAD 3,422,901

RETR I EVABLE WELL PACKER wwf/UL Jan. 21, 1.969 M. B. CONRAD yRETRIEVABLE WELL PACKER Sheet 3 of 3 Filed March 30, 1967 INVENTOR.M477N COA/164@ United States Patent O 3,422,901 RETRIEVABLE WELL PACKERMartin E. Conrad, Carpinteria, Calif., assignor to Baker Oil Tools,Inc., City of Commerce, Calif., a corporation of California Filed Mar.30, 1967, Ser. No. 627,190 U.S. Cl. 166-134 17 Claims Int. Cl. E21b23/06 ABSTRACT OF THE DISCLOSURE A well packer that includes a mandrelhaving portions of larger and smaller diameter, a resilient annularsealing member around the larger portion of the mandrel, and slipassemblies having shoulders engaging the ends of the sealing member. Theshoulders are movable toward each other in response to an upward forceon the mandrel for compressing the sealing member and expanding itoutwardly. A force-responsive element disconnects the mandrel from theslips upon imposing a predetermined downward load, after which themandrel may be moved to position the smaller diameter portion within theannular member, relieving the end load on the shoulders of the slipassemblies. The mandrel then, when pulled upwardly further, releases theslips and removes the tool from the well as a unit.

BACKGROUND OF THE INVENTION Field of the invention This inventionpertains to well bore tools, such as well packers or the like of theretrievable type.

Particularly, well packers of the double holding type are very difficultto release after they have been set in the well casing and subjected tohigh differential pressures tending to securely engage lthe upwardly anddownwardly holding slips with the well casing while the packing elementis disposed in sealing engagement with the well casing. Morespecifically, such packers may be diriicult to release due to the factthat the deformed elastomeric packing element may -be subjected tosevere compressive forces which react on the anchor slip mechanismstending to maintain the latter in forceful anchoring engagement with thewell casing, even though the differential pressure across the packerassembly may have been relieved.

Summary of the invention The tool of `this invention includes a mandrelhaving a portion circumscribed by at least one resilient annular packingring and an adjacent portion of smaller diameter. A slip assembly islocated at either end of the packing ring, presenting shoulders that canbe advanced toward each other to exp-and the packing ring outwardlyagainst the wall of the well casing to accomplish the seal. This isachieved by the application of an upward force on the mandrel which isresisted by drag blocks, enabling the slips to become set and the toolto become packed off. For releasing the tool, a downward force isapplied to shear orf the tooth of a ratcheting ring that engages thecone of one of the slip assemblies and resists downward movement of themandrel relative to the slips and the sealing element. Once this hasbeen sheared, tension screws are pulled apart so that the mandrel canmove relative to the slips, permitting a split ring to expand outwardlyinto an annular space around the mandrel. Previously, this ring wasreceived in recesses both in the mandrel and in the lower slip assembly,connecting these two elements so that an upward force on the mandrelcould be translated into the slips to pack off the tool. With the splitring out of the recess and in the annular space, however, the mandrelthen can move relative to the slips and the sealing member, 'bringingthe portion of smaller diameter adjacent the sealing element andrelieving the compression upon it. This takes olf the end load from thecones of the slip assemblies, so that further axial movement of themandrel causes cooperating shoulders to release the slips and free thetool from restraint within the well. Release is complete so that thetool cornes out of the well readily.

An object of this invention is to provide an improved well packer.

Another object of this invention is to provide a well packer released bylongitudinal loading and without rotation.

A further object of this invention is to provide a well packer that isreliable and 0f relatively simple and low cost construction.

An additional object of this invention is to provide a well packer thatis run into the well, packed olf, released and removed withoutdifficulty or complications.

Yet another object of this invention is to provide a well packer whichwill remain in the packed-off condition indenitely until release takesplace.

These and other objects will become apparent from the following detaileddescription taken in connection with the accompanying drawing.

Brief description of the drawing FIGURES la and lb together constitute alongitudinal sectional view of the well packer of this invention as itis being run into a well;

FIGURE 2 is an enlarged fragmentary sectional view of the portion of thepacker that includes the ring which is sheared subsequently when thetool is to be released;

FIGURE 3 is an enlarged fragmentary sectional view illustrating theconnection between the lower slip assem- -bly and the mandrel throughthe split annular ring;

FIGURES 4a and 4b together constitute a longitudinal sectional view ofthe tool in the well casing, similar to FIGURES la and lb, but with thetool in the packed-oli condition;

FIGURES 5a and 5b together constitute a longitudinal sectional view ofthe tool following release as it is being removed from the well; and

FIGURE 6 is an enlarged fragmentary sectional view illustrating amodification in which the ring that is sheared to begin the releasecycle is provided with an outwardly projecting tooth.

Description of the preferred embodiment As illustrated in FIGURES la andlb, the retrievable packer 10 of this invention is being lowered by ahead assembly 11 at the end of a tubing string 12 into a well casing 13.As illustrated, the packer 10 is to be set subsequently by manipulationof the tubing, although optionally it can be adapted for wire linesetting. The upper portion of the assembly 11 includes an internallythreaded tubular member 14 that is connected to the tubing string 12.The opposite end of the member 14 threads into a short sleeve 15 thatcircumscribes a ring 16 to 'which it is connected by a shear screw 17.The ring 16 has an upper surface bearing against the lower end shoulderof an annular member 18 that is threaded onto the mandrel 19 of thepacker assembly 10. The interior of the tubular member 14 also receivesa member 20 provided with seals 21 and 22, which prevent uid leakagealong the surface of the mandrel 19 or around the exterior of theelement 20. The upper end of the mandrel 19 is provided with teeth 24which mate with corresponding teeth 25 on the lower end of an annularmember 26 which is attached to and integral with the member 14.

Beneath the head assembly 11, the mandrel 19 has an externally threadedportion 27 which is received within a threaded ring 28. The lattermember is positioned at the upper end of a tubular housing 29 to whichit is secured by set screws 30. The tubular housing 29 comprises aportion of a drag means 31, which provides a resistance to movement ofthe tool in the well casing and may be similar to that illustrated inPatent 3,135,329. Briefly, the tubular housing 29 is provided with aplurality of longitudinally extending slots 32 spaced circumferentiallyaround the tubular housing 29.

Within the slots 32 are drag blocks 33, which are biased outwardly inthe radial direction by compression springs 34 and 35. The springs causethe drag blocks to bear against the inner surface of the casing 13 toprovide a yieldable resistance to the movement of the toollongitudinally within the casing. Flanges 36 and 37 overlap the dragblocks at the slots 32, so that the drag blocks are retained when thetool is removed from the well casing.

Below the friction means 31 is a slip assembly 38, which also may besimilar to the corresponding item illustrated in Patent 3,135,329. Theindividual slip elements 39 are retained by a ring 40 which, in turn, iscoupled to the tubular housing 29 by a split ring 41. The latter elementhas an annular recess in its inner surface that receives flanges 42 and43 of the tubular housing 29 and the ring 40, respectively, in effectingthe connection between the members 29 and 40. Unlike the design shown inPatent 3,135,329, there is a. ring 44 circumscribing the mandrel 19 atthe juncture of the members 29 and 40. The ring 44 bears against thesurface of the mandrel, While there is a clearance inwardly of themembers 29 and 40.

The slip elements 39 are T-shaped, each having a base portion 45received in an upwardly and outwardly inclined slot 46 in the ring 40.At the opposite end, the slips t include wickers 47 facing the wall ofthe casing, beneath which are downwardly sloping surfaces 48 adjacentsimilarly inclined surfaces 49 forming the walls of longitudinallyextending recesses 50 in the upper end of a tubular member 51. Along thesides of the slips 39 are ribs 52 that t within complementary slots 53in the member 51 at the recesses 50.

The lower end of the tubular member 51 terminates in a shoulder 54circumscribing an annular ridge 55 on the mandrel 19. Beneath the endshoulder 54 of the member 51 is a series of three resilient elastomericpacking elements 56, 57 and 58. Metal rings 59 and 60 separate theadjacent packing rings, being interposed between the ends of packingmembers 56 and 57 and between the ends of members 57 and 58. The lowerend of the bottom packing member 58 engages the upper radial shoulder 61of an annular member 62 that is threaded onto the upper end of a tubularelement 63 which forms a portion of a lower slip assembly 64. The latterassembly corersponds generally to the upper slip assembly 38, includinga plurality of individual slip elements 65 having wickers 66 on theirouter surfaces, and the slip elements 65 being received at their upperends in recesses 67 in the member 63. This places the inclined surfaces68 of the slip members 65 adjacent the complementarily inclined surface69 of the tubular member 63. The base portions 70 of the slip membersfit within inclined slots 71 in a sleeve member 72.

The interior surface of the tubular member 63 includes an inclinedshoulder 73 which, in the position of FIG- URE lb is adjacent a similarshoulder 74 formed on the periphery of the mandrel 19. Beneath theshoulder 74, the intermediate mandrel portion 75 is of reduced outsidediameter.

Above the shoulder 73, the mandrel includes teeth 76 on its periphery.As best seen in FIGURE 2, each tooth 76 includes a radial surface 77which intersects a surface 78 that is inclined downwardly and outwardlyfrom the root to the crest of the tooth. A split ring 79 is partiallyreceived within a recess 80 in the inner surface of the member 62 at theend of the tubular element 63. The

ring 79 includes an inwardly projecting tooth element 81 which iscomplementary to the teeth 76 of the mandrel 19. Thus, the tooth element81 includes a lower surface 82, which inclines downwardly and outwardlyfrom its crest to its root. Above the inclined surface 82 is a radialsurface 83. The ring 79 is of resilient material and has a free positionwith a smaller diameter than the outside of the mandrel at the teeth 76,so that the ring 79 is biased inwardly against the mandrel and away fromthe bottom of the recess 80.

The lower end of the sleeve member 72 is threaded into a short annularmember 85 the lower end of which, in turn, is received in the upper endof a collar 86. Screws 87 and 88 extend longitudinally through thecollar 86 and are threaded into the end of the member 85, connecting themembers 85 and 86.

The inner lower corner of the sleeve member 72 is recessed to provide aradial shoulder 89 and a circumferential surface 90 adjacent a splitring 91. The inner circumference of the split ring 91 is received in anannular recess 92 on the outer circuference of the mandrel section 75.The mandrel includes a bottom section 93tl1at threads onto theintermediate section 75, providing with its upper end the lower radialwall of the annular recess 92. The split ring 91 is resilient and has alarger free diameter than that illustrated in FIGURE 1b, so that thecircumferential surface 90 of sleeve member 72 at its lower inner cornerholds the split ring 91 inwardly within the recess 92, when the packeris conditioned for running and when the packer is set in the casing 13.

Beyond the `bottom end of the member 72 and between the inner and outersurfaces of the member 85 and the lower mandrel section 93 is an annularspace 94, access to which is provided by threaded openings 95 in thewall yof the annular member 85. Screws are inserted in the openings 95to force the split annular ring inwardly into the recess 92 duringassembly of the tool, after which those screws are removed as sleevemember 72 holds the ring 91 in the recess.

The bottom end of the collar 86 includes an inturned ange 96, which ispositioned immediately below an annular ridge 97 projecting outwardlyfrom the outer circumferential surface of the lower mandrel section 93.

A ring 98 is threaded onto the bottom end of the lower mandrel section93, providing a radial shoulder 99 at its upper end projecting outwardlyfrom the mandrel section 93.

The tool of this invention is lowered into the well casing 13 with theparts in the relationship illustrated in FIGURES la and lb. While thedrag blocks 33 engage the wall of the casing, the remaining componentsof the device are retracted and clear the surface of the casing. As thetool is being run in, the screws 87 and 88 hold the tubular member 72 inthe relative longitudinal position shown, preventing any upward movementof the member 72 relative to the mandrel because of their connection tothe collar 86 and the interengagement of the flange 96 and the ridge 97on the mandrel. This assures that the member 72 does not shift away fromthe split ring 91 and maintains the split ring confined in the annularrecess 92.

After the desired level within the well has been reached, the device ispacked off to the position of FIGURES 4a and 4b. To accomplish this, rstthe mandrel 19 is rotated to disconnect the threaded portion 27 from thering 28 at the upper end of the tubular housing 29. Rotation isaccomplished through the interengagement of the teeth 24 of the mandreland the teeth 25 of the head assembly 11. The friction means 31 throughthe drag `blocks 33, hold the ring 28 against turning as the mandrel isrotated, enabling the threads 27 on the mandrel 19 and the cornplementalthreads in the ring 28 to be disconnected.

Next, the mandrel 19 is subjected to an upward pull. This upward forceis transmitted through the split ring 91 and the shoulder 89 at theinner lower corner of the sleeve 72 which it engages, through the bottomslip assembly 64, the packing elements 56, 57 and 58, to the upper slipassembly 38. In view of the resistance to movement afforded lby the drag`blocks 33, the upper slip elements 39 are set as they slide outwardlyalong the inclined surfaces 49 to bring the wickers 47 into contact withthe wall of the casing 13. Additionally, the packing elements 56, 57 and58 become compressed between the shoulders 54 and 61 of the members 51and 62, respectively. With the inner circumferential surfaces of themembers 56, 57 and 58 being confined by the periphery of the mandrel 19,the packing elements are squeezed outwardly to contact the wall of thecasing and form a tight seal therewith. The lower slip assembly 64 also`becomes set as the slips 65 are brought outwardly so that their wickers66 engage the wall of the casing 13. Setting of the tool, therefore,requires merely the rotation of the mandrel, followed by an upward pull,which causes it to become securely packed off, in which condition itwill remain for an indefinite period of time.

As the tool is packed off, the annular mandrel 19 moves upwardlyrelative to the member 62 and the tubular member 63. When this occurs,the tooth 81 of the ring 79 slips over the teeth 76 of the mandrel 19,ending up at some location intermediate the ends of the toothed section-of the mandrel. This movement is possible because the ring 79 is split,and hence can be expanded as the inclined surfaces 78 of the teeth 76,by engaging the inclined surface 82 of the tooth 81, cam the ring 79outwardly. The recess 80 is made sufiiciently deep to allow the ring 79to 'be expanded an amount such that it can slip from one tooth 76 to thenext. A ratcheting effect is accomplished in this manner.

As the mandrel is pulled upwardly by the head assembly 11 in setting thetool, the screw 17 shears, breaking the connection between the memberand the ring 16. Therefore, the member 14, which is connected to thetubing string 12, is permitted a limited amount of upward movementrelative to the mandrel 19 until the ange 100 of the sleeve 15 engagesthe lower end of the ring 16. This disengages the teeth 24 of themandrel from the teeth 25 of the ring 26, so that the head assembly 11thereafter can be rotated relative to the tool without also turning themandrel.

To release the packer, the first step is to impose a downwardly directedforce on the mandrel 19. This force is resisted by the split ring 79, inview of the engagement between the radial surface 83 of the tooth 81 andthe corresponding radial surface 77 of one of the teeth 76 of themandrel. In releasing the tool, the downward force is made great enoughto shear off the tooth 81 of the ring 79, so that thereafter the mandrelencounters no resistance from the ring 79.

The downward force on the mandrel also is resisted by the screws 87 and88. This comes about because the ridge 97 of the lower mandrel section93 engages the inturned ange 96 of the collar 86 through which thescrews 87 and 88 extend. Consequently, the force on the mandrel istransferred into the collar 86 and to the screws 87 and 88. The ends ofthe screws 87 and 88 are held fast by their threaded connection to thememlber 85 which connects to the lower slip assembly.

After the tooth 81 of the ring 79 has been sheared, the screws 87 and 88absorb the entire downward thrust in tension. This causes the screws 87and 88 to elongate and ybecome pulled apart.

The mandrel then, through the shoulder 101 at the upper end of therecess 92, moves the split ring 91 downwardly relative to the member 72until the split ring 91 reaches the space 94. When this occurs, beingfree from the restriction imposed by the circumferential surface 90 ofthe member 72, the ring springs outwardly into the space 94. This freesthe split ring 91 from the upper end of the lower mandrel section 93 andthe shoulder 89 of the member 72. Consequently, the connection betweenthe mandrel and the lower slip assembly is broken.

The mandrel then may move upwardly relative to the slip assemblies andthe packing elements.

After imposing the downward force to shear the tooth 81 of the ring 79and sever the screws v87 and 88, as described above, and releasing thesplit ring 91, an upward force then is applied to the mandrel 19. Thispulls the mandrel up relative to the slip assemblies and the packingelements 56, 57 and 58, which remain stationary, locked in place againstan upward force by the upper slip assembly 38. As the upward movementcontinues, the shoulder 74 of the mandrel 19 passes through the threepacking elements S6, 57 and 58. As the shoulder moves through thepacking members, they are brought into adjacency lwith the intermediateportion 75 of the mandrel, which is of reduced diameter. As a result,the inner surfaces of the packing rings no longer are held outwardly asfar as before by the periphery of the mandrel. The compression on thepacking elements 56, 57 and 58 is relieved in this manner, withattendant reduction in the end loading on the shoulders 54 and 61 of theslip assemblies. Also, the outward force of the packing elements againstthe casing is reduced.

Further upward movement of the mandrel causes the annular ridge 55 ofthe mandrel to be brought into engagement with the ring 44 thatcircumscribes the mandrel between the tubular housing 29 and the ring40. With the members 29 and 40 being connected -by the member 41, theengagement between the ridge 55 and the ring 44 causes an upward pull onthe member 40 of the upper slip assembly 38, which, in turn, pullsupwardly on the slip members 39. This releases the upper slips, Theprevious relief of the end load on the slip assembly resulting from thereduction of compression of the packing elements makes this release ofthe slips possible. The lower slips l65 then also are released as themandrel is moved upwardly. The tool thus is free to be brought out ofthe well casing.

As the mandrel continues to move upwardly, the ridge 97 on the lowermandrel section 93 is brought into engagement with an inner shoulder 102near the upper end of the tubular member 72. This causes the lower slipassembly to travel with the mandrel as the tool is withdrawn from thewell. Also, the collar 86 is picked up by the shoulder 99 of the ring 98at the lower end of the mandrel. Thus, the entire tool is pulled fromthe well as a unit, with the parts in the relationship shown in FIG-URES 5a and 5b. Other than the engagement of the drag blocks 33 with thewell casing 13, the elements of the tool are completely retracted forremoval and offer no resistance to the movement of the tool.

Consequently, tool removal becomes a simple operation, requiring onlythe appilcation first of a downward force followed by an upward pull onthe mandrel. No rotation is required. The shifting of the mandrel tobring the portion of smaller diameter within the packing elementsrelieves the compression and reduces the end loading on the slipassemblies, so that further movement of the mandrel can release theslips.

The ring 79 is constructed to withstand some downward loading, so thatthe packer will not be released prematurely. Thus, relatively smalldownward loads can be absorbed lwithout shearing the tooth 81 to beginthe release cycle. It is a simple matter to apply an adequate downwardload on the tool, however, to shear the tooth 81 and effect the releaseat the appropriate time.

It is obvious that the components of the packer of this invention mayhave some modification within the scope of the present invention. Forexample, the ratcheting ring may be constructed with its tooth facingoutwardly, as seen in FIGURE 6, rather than with a tooth on the inside,as described above. In the design of FIGURE 6, the ring 103 has a tooth104 on its periphery adjacent complementary teeth 105 on an annularmember 106. The latter element corresponds to the member 63 describedabove, and provides the cone for the lower slips, The ring 103 is split,as was the ring 79, and is slid along the teeth 105 when the tool isset. In that position, it resists downward movement of the mandrel untilthe tooth 104 is sheared off. Generally, it is preferred to use the ringin the form of the member 79 because of ease of assembly of the tool.

The foregoing detailed description is to be clearly understood as givenby way of illustration and example only, the spirit and scope of thisinvention being limited solely by the appended claims.

I claim:

1. A device for use in a well comprising a body adapted to be introducedinto a well, said body having a first portion of a first transversedimension and a second portion of a second and smaller transversedimension, a compressible member, releasable means for normally holdingsaid body and said compressible member with said compressible memberdisposed about said first portion of said body, means for compressingsaid compressible member while inwardly confining portions of saidcompressible member by said first portion of said body, and means forreleasing said releasable means for allowing movement of said bodyrelative to said compressible member to bring said second portion ofsaid body into a position of adjacency with said compressible member forremoving `from said compressible `member the inward confinement of saidfirst portion so as to reduce the compression thereof.

2. A device for being positioned in a well comprising a body adapted tobe introduced into a well, said body having a first portion of a rsttransverse dimension and a second portion of a second and smallertransverse dimension, at least one resilient compressible memberadjacent said first portion of said body, abutment means adjacent eitherend of said compressible member, means for advancing said abutment meansrelatively toward each other for compressing said compressible memberbetween said abutment means while said compressible member is inwardlyconfined by said first portion of said body for thereby expanding saidcompressible member outwardly responsive to movement of said body in onelongitudinal direction in said well, and releasable means for allowingmovement of said body further in said one longitudinal directionrelative to said compressible member to bring said second portion ofsaid body into a position of adjacency with said compressible member forremoving from said compressible member the inward confinement of saidfirst portion so as to reduce the compression thereof.

3. A device for being positioned in a well comprising a mandrel adaptedto be introduced into a well easing, said mandrel having a first portionof a first exterior diameter and a second portion of a second andsmaller exterior diameter, at least one resilient annular membercircumscribing said mandrel at said first portion thereof, a shouldermeans at either end of said resilient annular member, means for movingsaid shoulder means relatively toward each other to a position ofrelative adjacency in response to longitudinal movement of said body inone longitudinal direction in said well for thereby compressing saidresilient annular member between said shoulder means while confining theinner part of said resilient lannular member by said first portion ofsaid mandrel thereby to expand said resilient annular member outwardly,means for holding said shoulder means in said position of relativeadjacency for .thereby maintaining said resilient annular member socompressed, and means for allowing movement of said mandrel relative tosaid resilient annular member while said shoulder means are so held forshifting said second portion of said mandrel to a position within saidresilient annular member for thereby reducing the inward confinement ofsaid resilient annular member and the compression thereof.

4. A well packer comprising a mandrel adapted to be inserted into a wellcasing, said mandrel having a first portion of a first outer diameterand a second portion of a second and smaller outer diameter, at leastone resilient annular member circumscribing said first portion of saidmandrel, a first shoulder means adjacent one end of said annular member,a second shoulder means adjacent the opposite end of said annularmember, actuating means including means connecting said mandrel to saidshoulder means for causing said shoulder means to move relatively towardeach other to a position of relative adjacency upon axial movement ofsaid mandrel in one direction for thereby compressing said annularmember therebetween while confining the inner part of said annularmember by said `first portion of said mandrel so that the outer part ofsaid annular member is forced outwardly against the wall of said wellcasing, holding means for holding said shoulder means in said positionof relative adjacency and for engaging the wall of a well casing forholding said annular member against longitudinal movement in said wellcasing, means responsive to axial movement of said mandrel in the otherdirection while said shoulder means are in said position of relativeadjacency for disconnecting said mandrel from said shoulder means forallowing said mandrel to move further axially in said one directionrelative to said annular member for bringing said second portion of saidmandrel to a position within said annular member and relieving theinward confinement of said annular member and the compression thereof,and means for releasing said holding means for allowing removal of saidwell packer from the well casing.

5. A well packer comprising an elongated mandrel adapted to be insertedinto a well casing, said mandrel having a first portion of a first outerdiameter and a second portion of a second and smaller outer diameter, atleast one resilient annular member circumscribing said first portion ofsaid mandrel, slip means, said slip means including a shoulder adjacenteither end of said annular member, friction means for engaging the wallof a well casing and providing a limited resistance to movement relativethereto, means connecting said mandrel to said slip means forcooperating with said friction means to move said shoulder meansrelatively toward other each to a position of relative adjacency uponmovement of said mandrel in one longitudinal direction, said slip meansincluding means movable outwardly upon such movement of said mandrel forgripping the wall of a well casing to hold said resilient annular memberagainst movement in either direction in said well casing, said annularmember being compressed between said shoulder means when said shouldermeans are so moved to said position of relative adjacency and confinedinwardly by said first portion of said mandrel so that the periphery ofsaid annular member is expanded outwardly for engagement with the Wallof a well casing, said connecting means including means fordisconnecting said mandrel from said slip means upon the application ofa predetermined force and movement of said mandrel in response theretoin the opposite direction, said mandrel being subsequently movable insaid one direction when so disconnected for bringing said second portionthereof into said annular member for relieving the inward confinementand the compression of said annular member, and means responsive to saidsubsequent movement of said mandrel in said one direction for retractingsaid slip means for releasing said well casing and allowing removal ofsaid well packer from a well casing.

6. A well packer comprising a mandrel adapted to be inserted into a wellcasing, said mandrel having a first portion of a first outer diameterand a second portion of a second and smaller outer diameter, at leastone resilient annular member circumscribing said first portion of saidmandrel, friction means carried by said ymandrel for providing a limitedresistance to movement in said well casing, a first slip means carriedby said friction means and providing a first shoulder adjacent one endof said annular member, a second slip means providing a second shoulderadjacent the opposite end of said annular member, means connecting saidmandrel to one of said slip means for cooperating with said frictionmeans to move said shoulders relatively toward each other to a positionof relative adjacency upon upward movement of said mandrel, therebycompressing said annular member between said shoulders while confiningthe inner surface of said annular member by the periphery of said firstportion of said mandrel and expanding the outer surface of saidresilient annular member outwardly into engagement with the adjacentwall of said well casing, and for causing said slip means to expandoutwardly for engagement with the wall of said well casing to hold saidshoulders in said position of relative adjacency, means responsive to asubsequent downward force on said mandrel of a predetermined magnitudefor disconnecting said mandrel from said one slip means for allowingsaid mandrel thereafter to move relative to said annular member to bringsaid second portion of said mandrel within said annular member to reducethe inward confinement of said annular member and the compressionthereof, and means for disengaging said slip means from the Wall of saidwell casing upon further movement of said mandrel for thereby releasingsaid well packer and permitting removal thereof from said well casing.

7. A device as recited in claim 6 in which said means responsive to adownward force on said mandrel includes a circumferentially expansibleand contractible ring,

said ring having a tooth thereon, said mandrel and one of said slipImeans cooperating to define a recess receiving base portions of saidring, and teeth engageable with said tooth of said ring,

said teeth having inclined surfaces for allowing said ring to moverelative thereto upon relative upward movement of said mandrel, andabutment surfaces for abutting said tooth of said ring for resistingrelative downward movement of said mandrel,

whereby said tooth of said ring is caused to shear off upon theimposition on said mandrel of said downward force of predeterminedmagnitude. 8. A device as recited in claim 6 in which said meansconnecting said mandrel to said one slip means includes a split annularmember of resilient mtaerial, an annular recess means in said mandrelreceiving said split annular member,

said split annular member having a free diameter greater than thediameter of said annular recess, said slip means having a surfaceholding said split annular member in said recess,

said surface of said slip means being moved away from said split annularmember upon imposing on said mandrel said downward force ofpredetermined magnitude,

thereby to allow said split annular member to assume its free diameterand leave said annular recess for disconnecting said mandrel from saidone slip means. 9. A device for being positioned in a well comprising abody adapted to be introduced into a well bore, said body having a firstportion of a first transverse dimension and a second portion of a secondand smaller transverse dimension, at least one resilient compressiblemember circumscribing said first portion of said body, shoulder `meansadjacent either end of said compressible member, and means for advancingsaid shoulder means relatively toward each other in response to movementof said body for compressing said compressible member between saidshoulder means while said compressible member is inwardly confined bysaid first portion of said body and thereby expanding said compressiblemember outwardly,

said 'means for advancing said shoulder means including an abutment onsaid body, an abutment on said shoulder means, an element interposedbetween said abutments for transmitting force from said body to saidshoulder means,

said element having a normal position of disengagement from saidabutments, and means for holding said element in engagement with saidabutments,

said holding means including means responsive to a predetermined forceon said body for `releasing said element to said element to disengagesaid abutments, said body being movable reltaive to said shoulder meansand said compressible member when said abutments are so disengaged forbringing said second portion of said body into a position of adjacencywith said compressible member for removing from said compressible memberthe inward confinement of said first portion of said body so as tolreduce the compression of said compressible member.

10. A device as recited in claim 9 in which said body includes anannular recess for providing said abutment on said body,

said shoulder means including Ian annular member having a recessdefining said abutment of said shoulder means, and a circumferentialsurface, said element comprising a split ring received in said recessand having a free diameter greater than said recess,

whereby when said annular member is in its free position it disengagessaid abutments,

said circumferential surface engaging the periphery of said split ringfor maintaining said split ring in said recess, and said meansresponsive to force on said body cornprises a member interconnectingsaid body and said shoulder means and severable upon being subjected tosaid predetermined force.

11. A device as recited in claim 10 in which said member connecting saidbody and said shoulder means cornprises a tension member extendingtherebetween.

12. A well packer comprising a mandrel adapted to be inserted into awell casing,

said mandrel having a first portion of a first diameter,

and a second portion of a second and smaller diameter below said firstportion,

at least one resilient annular member circumscribing said first portionof said mandrel,

a first slip means above said annular member,

a second slip means ybelow said annular member,

said first slip means defining a first shoulder adjacent one end of saidannular member,

said second slip means defining a second shoulder adjacent the oppositeend of said annular member,

friction means on said mandrel above said first slip means for providinga limited resistance to axial movemnt in a well casing,

each of said slip means including a member defining a sloping surfaceand an element movable along said sloping surface to an outer positionfor engaging a well casing,

a shear member interposed between said member of said second slip meansand said mandrel,

said member of said second slip means and said mandrel including meansengaging said shear member for allowing said mandrel to movelongitudinally upwardly relative to said member of said second slipmeans while resisting through said shear member longitudinal downwardmovement of said mandrel following said longitudinal upward movementthereof, said shear member being frangible upon the exertion of apredetermined downward force on said mandrel for allowing such downwardmovement of said mandrel following said upward movement thereof, a splitannular member,

said mandrel including an annular recess receiving inner portions ofsaid split annular member, said recess having an abutment at either endthereof for engaging said split annular member for moving said splitannular member with said mandrel, said split annular member beingresilient and having a free diameter larger than the periphery of saidmandrel, said second slip means including a surface confining said splitannular member to retain said inner portion thereof in said annularrecess, said second slip means including an abutment engageable by outerIportions of said split annular member for transmitting upwardlongitudinal force from said mandrel to said second slip means,

whereby upon the exertion of an upward force on said mandrel saidfriction means resists upward movement of said rst slip means and saidmandrel applies a force through said split annular member and saidabutments to advance said slip 4means relatively toward each other sothat said resilient annular member is compressed between said shouldermeans while being confined by the periphery of said first portion ofsaid mandrel so that said resilient annular member is expanded outwardlyfor sealing engagement with the wall of a well casing, and uponapplication of a subsequent downward force of said predeterminedmagnitude said shear member is fractured for allowing said mandrel tomove downwardly relative to said slip means and said resilient annularmember,

said split annular member being disengageable from said surface and saidabutment of said second slip means upon such subsequent downt wardmovement of said mandrel,

whereby upon subsequent upward movement of said mandrel said secondportion of said lmandrel is moved to a position within said resilientannular member for relieving the compression thereof and the end loadingon said shoulders of said slip means, said mandrel including means forreleasing said slip means upon further upward movement of saidy mandrelfor thereby releasing said well packer from a wall casing and permittingremoval thereof. 13. A device as recited in claim 12 in which said shearmember comprises a split ring, said member of said second slip meanshaving a recess therein receiving said split ring, said ring having atooth protruding therefrom,

inwardly Said mandrel having teeth on the periphery thereof for meshingengagement with said tooth of said ring, said teeth of said mandrel andsaid tooth of said ring having inclined surfaces for allowing said ringto slip over said teeth progressively upon relative upward movement ofsaid mandrel, said teeth of said mandrel and said tooth of said ringhaving radially directed surfaces interengageable for resisting relativedownward movement of said mandrel,

whereby to effect such downward movement said tooth of said ring must besheared.

14. A device as recited in claim 12 in which said shear member comprisesa split ring.

said mandrel having a recess receiving said split ring,

said ring having a tooth protruding outwardly therefrom,

said member of said second slip means having teeth thereon for meshingengagement with said tooth of said ring,

Isaid teeth of said member of said second slip means and said tooth ofsaid ring having inclined surfaces for allowing said ring to slip oversaid teeth progressively upon relative upward movement of said mandrel,

said teeth of said member of said second slip means and said tooth ofsaid ring having radially directed surfaces interengageable forresisting relative downward movement of said mandrel,

whereby to effect such downward movement said tooth of said ring mu-stbe sheared.

15. A well packer for packing olf a well casing comprising: an elongatedtubular mandrel having axially spaced `body portions of large and smalldiameter; annular packing means disposed about said large diameter bodyportion; upwardly holding anchor means and downwardly holding anchormeans at opposite ends of said packing means; said. anchor meansproviding opposing shoulders engaged with said packing means; frictiondrag means for effecting actuation of said anchor means and movement ofsaid shoulders one toward the other to expand said packing meansoutwardly responsive to longitudinal movement of said mandrel relativeto said friction drag means in one direction; first releasable connectormeans for connecting said mandrel to said friction drag means to preventsuch movement of said mandrel; second releasable connector means forallowing limited movement of said mandrel in said one directionfollowing release of said first releasable connector means, said secondreleasable connector means ybeing releasable upon movement of saidmember longitudinally in the other direction to allow further movementof said mandrel in said one direction to dispose said small mandrel bodyportion in said packing means to relieve outward expansion thereof.

16. A well packer for packing off a well casing comprising: an elongatedtubular mandrel having axially spaced body portions of large and smalldiameter; annular packing means disposed about said large diameter bodyportion; upwardly holding anchor means and downwardly holding anchormeans at opposite ends of said packing means; said anchor meansproviding opposing shoulders engaged with said packing means; frictiondrag means -for effecting actuation of said anchor means and movement ofsaid shoulder one toward the other to expand said packing meansoutwardly responsive to longitudinal movement of said mandrel relativeto said friction drag means in one direction; rst releasable connectormeans yfor connecting said mandrel to said friction drag means toprevent such movement of said mandrel; and second releasable connectormeans between said mandrel and said anchor means releasable for allowinglongitudinal movement of 'said mandrel for disposing said small 13 14 imandrel portion in said packing means to relieve out- References Citedward expansion thereof. UNITED STATES PATENTS 17. A well packer asdefined in claim 16, wherein said 2 652 894 9/1953 Brown et al 166 134rst releasable connector means comprises a threaded 5 2:944604 7 /1960Baker 'l 166 134 connection between said friction drag means and Said hmandrel; and second releasable connector means includes JAMES A'LEPPINK: Pnmay Examme means releasably responsive to longitudinalmovement of U.S CL X'R.

said mandrel in the other direction. 166-139

